Abstract: Alloying additions have an important effect on in-situ chemical reaction
4Al+Si3N4=4AlN+3Si to synthesis (AlN+Mg2Si)/Mg composites. Using the Wilson equation and
an extended Miedema model, the activity in a multiple-component system can be calculated，and
then the Gibbs free energy can be calculated. In final, the influence of alloying element additions on
the in-situ chemical reaction at high temperature is investigated from a thermodynamic viewpoint.
Abstract: The effect of the alloying element additions on in-situ chemical reaction to synthesize
particulate reinforced TiC/Mg composites was evaluated from the viewpoint of thermodynamics.
The influences of alloying elements on the changes of the activity coefficient and the excess free
energy in molten magnesium were calculated. The results show that additions, such as Nd, La, Ca,
Cu and Zr can promote TiC formation, at the same time hinder the brittle TiAl3 phase formation.
Abstract: TiB2 particulate reinforced magnesium matrix composites were successfully fabricated
by adding a TiB2–Al master alloy processed via the flux-assisted synthesis (FAS) reaction into
molten magnesium. X-ray diffraction (XRD) analysis and microstructural characterization of the
TiB2–Al master alloy revealed the formation and uniform distribution of TiB2 reinforcements. By
stirring, magnesium matrix composites with dispersed homogenously TiB2 particles can be obtained.
Microstructural characterization of the TiB2/Mg composites revealed retention of hexagonal or
rectangular TiB2 particulates with the size of about 1 μm.
Abstract: In this paper, a three-phase composite with electrically conductive carbon black (ECCB)
and piezoelectric ceramic particles, PMN, embedded into butyl (PMN/ECCB/IIR) was prepared by
simple blend and mold-press process. Dynamic mechanical properties with various ECCB loading
were tested by dynamic mechanical analysis (DMA). DMA shows that the ECCB loading has
remarkable effect on the dynamic mechanical properties of the three-phase composite. The
temperature range of loss factor (tanδ) above 0.3 the composite was broadened by almost 100°C
and the maximum of loss factor shifts to higher temperature in the testing temperature range
respectively with increasing the ECCB loading. The piezoelectric damping theory was used to
explain the experimental results. The three-phase composites with proper composition can be used
as high damping polymer materials.
Abstract: In the present study, α-Si3N4 is prepared by using MgO and Al2O3 as the sintering
additives and spark plasma sintering (SPS) technique. The SPS sintering mechanism is discussed.
The relationship between the content of sintering additives, sintering temperature and relative
densities of the samples is analyzed. The results suggest that when the sintering temperature is
1300-1500°C, the content of sintering additives is 6wt.%-10wt.%, the relative density of sintered
samples is 64%-96%. When the sintering temperature reaches 1400°C, the content of sintering
additives is 10%, the samples can be fully dense sintered and the relative density can be up to 95%.
The sintering mechanism is liquid phase sintering. The bending strength of the sintered samples is
50-403MPa and has a close correlation with the relative density.
Abstract: A series of zirconia porous ceramics with different density are fabricated with commercial
zirconia powder and zirconia hollow balls by pressureless sintering technology. The microstructure
and phase transformation are characterized respectively by SEM and XRD testing methods. The
result indicates that the density and compressive strength depend greatly on zirconia powder content
at the same sintering temperature, and elevating sintering temperature just has a little effect on the
density and compressive strength for the samples of the same zirconia powder content. The XRD
diffraction patterns analysis shows that elevating sintering temperature is helpful to eliminate
monoclinic zirconia and the best sintering temperature should be beyond 1700°C.
Abstract: Potassium lithium niobate (KLN: K3Li2Nb5O15) films have been deposited on quartz
glass by Pulsed laser deposition (PLD) technique using a stoichiometric KLN target as starting
materials. By investigating the effects of both the oxygen pressure and the substrate temperature on
the structure of KLN films, optimum parameters have been identified for the growth of high-quality
KLN films. At 10Pa oxygen ambient pressure, tetragonal tungsten-bronze-type structure of KLN
films with (310) preferred orientation can be achieved at substrate temperatures in the range of
700-800°C. Optical studies indicate that the films are highly transparent in the visible-near-infrared
Abstract: Combustion synthesis of titanium diboride(TiB2) from titanium(Ti) and boron(B)
powders was studied by theoretical calculation and experimental analysis. In high temperature
range or in low temperature range, the calculated activation energies are 140KJ/mol or 355KJ/mol
respectively, which is described by a change from dissolution-precipitation controlled process to
diffusion-controlled process. With the increase of particle size of the raw materials, combustion
temperature and propagating rate will both reduce. The propagating rate decreases with the addition
of diluents. Further increase of diluents may result in a stop of the combustion wave halfway or
even a failure of ignition.
Abstract: The microstructures and tensile performance of B4C particulate reinforced 2024 Al alloy
matrix composites produced by mechanical alloying and common blending techniques were
investigated. The results showed that mechanical alloying was an effective way to fabricate the
particulate reinforced Al matrix composites over common blending. The samples by different mixing
techniques exhibited a clean and chemical products free interface. Tensile strength and elastic
modulus of the composites was higher than that of the based alloy at the expense of ductility. The
composites by common blending exhibited a more ductile fracture surface in contrast to specimen by
Abstract: In this paper, Ti-6Al-4V matrix composites reinforced with 5% or 10% TiB and TiC were
in situ synthesized by common casting and hot-forging technology utilizing the reaction between
titanium and B4C. The phase constituents were identified by XRD while transus temperatures were
determined by DSC and metallography. The evolution of microstructures was studied by optical
microscopy. The effects of reinforcements on the microstructures, tensile properties and fractures at
room temperature were discussed. The results show that yield strength and ultimate tensile strength
increased significantly while ductility decreased with reinforcements increasing. Fracture type
turned to brittle when reinforcements increased.